Cathode ray electrostatic printing or recording device



Sept 10, 1963 R. s. HOWELL CATHODE RAY ELECTROSTATIC PRINTING OR RECORDING DEVICE 2 Sheets-Sheet 1 Filed Aug. 31, 1961 m T. m M

R CHARD S. HOWELL kg; AGENT Sept. 10, 1963 R. S. HOWELL CATHODE RAY ELECTROSTATIC PRINTING 0R RECORDING DEVICE Filed Aug; 31. 1961 2 Sheets-Sheet 2 Fig.6

INV EN TOR.

RICHARD S. HOWELL Fig.

AGENT 'means in the envelope structure of such a tube. a particularly it has for its purpose to provide such a dual United States Patent O 3,103,606 CATHODE RAY ELECTROSTATIC PRINTING R RECORDHNG DEVICE Richard S. Howell, King of Prussia, Pa, assignor to Burroughs Corporation, Detroit, Mich, a corporation of Michigan V Filed Aug. 31, 1%1,Ser. No. 135,368 7 Claims. (Cl. 313-73) The invention hereinafter described and claimed has to do with electnostatic printing or recording heads, but more particularlly to a combined cathode-nay tube and electrostatic printing and recording head, whereby such printing or recording may be initiated by means of the cathode beam of the tube, in the manner described and claimed in the co-pending application of Robert E. Benn entitled Electron Tube Serial No. 131,337, filed August 14,-1961, and assigned to the assignee of the present invention.

The electrostatic recording process consists broadly of three steps. The first step comprises establishing, or printing, electrically charged areas on selected portions of the recording medium, which areas are representative of information. The second step consists of developing such charged areas on the recording medium, by making them visible, :Eor example. The third step, which is optional, consists in fixing or rendering such developed areas substantially permanent. In electrostatic process these three steps take place sequentially and .at physically separate locations. I

In the co-pending application Serial No. 729,847, filed April 21,- 1958, entitled Electrographic Recording Process and Apparatus, by Robert E. Benn, and Richard S. Sakauri, which, application is assigned to the assignee of I the present application, the advantages of positively initiating the establishment of a charged area on a recording medium by creating an electrical discharge between an initiating electrode and a' print electrode are set forth.

' In that co -pending application a separate pulse generating source. for each print electrode and each initiating electrode ofv a matrix print head is required. The simulta-' neous occurrence or application of print and initiating pulses to corresponding print and initiating electrodes iniate the establishment of a charged area on the recording medium located in a gap between the print and initiating electrodes of the print head and a back electrode.

It is brought out in the above identified Benn et al.

application Serial No. 729,847, that great simplification 3,ld3,h%

' Patented Sept. 19, 1963 driven by' the cathode-beam of such a tube and since the occurrence of the discharge from an initiating electrode to the adjacent printing or bar electrode which is connected to a suitable printing voltage, automatically brings the two electrodes within a few hundred volts of each other in potential, the voltage excursion of the initiating electrodes as a result of a secondary-emission phenomena is restricted, making the operation of the system less sensitive to the different secondary-emission characteristics of various types. 7

Briefly, in its broadest aspects, the'invention provides an electrostatic printing or recording head comprising a row of aligned pin electrodes and a bar electrode common to each pin and electrically insulated from each other, all sandwiched between and bonded to a pair of electrically insulating, preferably lead-glass rods, with an end of each pin and an edge of the bar exposed on one side, and only the opposite ends of the pin electrode on the opposite side. The head unit, in accordance with another aspect of the invention, is bonded to the envelope of a cathode-ray tube, over an opening therein, whereby the exposed pin and bar electrodes on one side are on the outside of the envelope and only the exposed ends of the pin electrodes on the opposite side are on the inside of the tube, thus to form the targets for the cathode beam during printing or recording. I

The invention will be more fully appreciated from the following description of the preferred embodiment thereof taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic plan view of a cathode ray tube incorporating a pin-bar electrostatic recording head in accordance with the invention;

FIG. 2 is a schematic elevational view of the cathode ray tube as seen in FIG. 1, and showing the head in association with a back electrode and a recording medium;

FIG. 3 is a perspective view of two glass rods used in the construction of the invention;

' FIG. 4 is a view similar to FIG.-4 but showing the condition of the two glass rods during fabrication of the print head;

FIG. 5 is a transverse sectional View of the recording herad illustrative-of its condition prior to final lapping or of the drawings and first to FIGS. 6 and 7, it is seen that entitled Electrographic Recording Apparatus, by Robert E. Benn, Richard S. Howell, and Richard S. Sakuari which application is assigned to the assignee of the present invention.

i The present invention has for its primary purpose to provide an electrostatic printing or recording head wherea electrode (initiating and printing) printing or recording More el'ectrode'printing or recording means which is easily, economically and efficiently fabricated.

A' particular advantage of a system taught in the above identified co-pending applications is that it is only in accordance with the preferred form, the invention comprises an aligned row of pin electrodes 10, a bar electrode 12 traversing the ends 14 of the pin electrodes, but electrically insulated therefrom by a thin layer of insulation 16 all bonded together, between and to a pair of electrically insulating rods 18 and 20, preferably of lead-glass,

by glass frit 21 thus to form the recording unit 22. The

envelope 24 (FIGS. 1 and 2) preferably the faceplate 26, of the cathode ray tube 23 is provided with an opening 30 over which the head 22 is hermetically sealed to the envelope. conventional shape in which the envelope 24 is elongated with a narrow neck portion 34 at one end and a flared end portion 36 at its opposite end across which the faceplate 26 is bonded. The narrow neck portion 34 houses a conventional beam producing gun 38and deflection plates 40 for directing a beam to the pin electrodes. In use, a back electrode 42. (FIG. 2) may be provided slightly spaced from the head to form a gap '44 through which a record medium 46 is threaded.

While the head may be fabricated in other ways, it

The cathode ray tube 28 may comprise one of Electrostatic Printing or Recording Devices, wherein the method described is as set forth hereinafter.

'Iwo electrically insulating rods 50 and 52(FIG. 3)

approximately A" square by 3" long are provided,-and may be cut from flat 4" thick lead-glass sheet.

As seen in FIG. 4 the rod 50 has wound upon it T a pitch of .010", and forapproxirnately 2" along the length of the rod;

The wireis oxidized by any suitable means, such as a V gas-oxygen flame, after which the glass frit 21 is applied to the rod in an amount snflicient to cover the winding with a melted layer of the frit. This step can be accomplished in an oven by the procedure outlined in the Coming Product Information Bulletin authored by L. C. Liptak, November 21, 1957, or by spreading, as with a thin metal spatula, a thin coating of melted frit to the rod after it has been heated and then heating the frit by a hand-held glass blowers gas-oxygen torch. The temperature should not be allowed to exceed approximately 550 C. 'whichis thesoftening point of the lead-glass rod.

. After cooling, one surface 58 (FIG. 5) of the so prepared rod 50 is ground or lapped upon the winding; po-

sitions 60 are just exposed through the frit coating 21,

, V as indicated by the line 62.

The rod 52 is now coated on one side 64' only, with a thin layer of glass frit 66, after which a strip 68 of Nichrome approximately .003" thick by ",wvide by 3" long which has been properly oxidized is layed on top of the frit along the length of rod 12 with a small. length 70 thereof, as seen in FIGS. 1 and 7, extending out past the end of the rod '52 to be used later-for connection purposes. The Nichrome strip 68 is layed off center with one of its edges 72 about from the edge of the rod,

. the exposed surface 74 of the Nichrorne strip, andwith a strip 76 of .0013" thic'kribbon glass between them.

Heat at approximately 550 C. is then applied along with moderate pressure until the frit fuses together and the rods are joined to become a'single integral unit.

The unit is then cooled and lapped, preferably on all sides, so as to removeall remaining unwanted parts, such as the excess, wire winding around the outside of. bar .50, and the excess glass as indicated by the heavy broken lines '7 8 on FIG. 5 thus to produce the finished head, whereby as seen in FIGS. 6 and 7, an edge 80 of the strip 12 and. the ends 14 of the remaining wire pora tions, which we will'now call. pins 10, as formerly desighated, are exposed on one side 84 and only the pin ends '86 on the opposite side 88. It is desirable that the length of the pins 10 sealed within the unit should be as short as possible in the area over which the bar 12 is in close proximity to the pins, .thus to minimize the capacity effect between the pins and the bark Therefore it is preferred to lap the unit from the'front' 84 that is, where both the edge 0300f the bar '12 and pin ends 14 will be exposed, until the bar becomes as narrow as possible without weakening the print head structure. Then'the inside surface 08 'of the unit, or that surface where only pin ends 86 will be exposed to the electron beam, is lapped down until the inside edge 90 of the bar 12 is almost exposed, but. V notquite, since it is essential that only the pins be struck by the beam.

The finished recording head 22 may be approximately .040 to .050" thick, and as long as desired, in the present case three inches.

The pin-bar unit as described above can now be sealed onto either a glass faceplate 26 of the cathode-ray tube 28, or even a metal faceplate such as is common in the industry today. 'In either case the recordinglmit is sealed over an opening on window 30 in the faceplate, and sealing can be accomplished by the use of well known glass frit techniques, as indicated at '96 in FIG. 7.

While there has been described only a single unitary pin-bar electrode, it is within the scope of the invention to provide a complete matrix of such electrodes, by assembling a plurality of such units, and sealing them tolines 97 in FIG. 6;

What is claimed is:

1. In a cathode ray electrostatic recording device having a nonconductive envelope, means in said envelope gether along edges 78 and 99, as indicated by the broken for generating and projecting a cathode beam, and a pin- 7 bar electrostatic recording head forming a part of the faceplate of said envelope, the improvement of a said head comprising an aligned row of pin electrodes closely spaced from each other, a bar electrode closely adjacent and traversing ends of said pin electrodes, a pair of electri-cally nonconduotive rod means, electrically non-conductive glass means insulating said pin electrodes from each other and from said bar electrode and sandwiching said electrodes between said rods and simultaneously a bonding said pin and bar electrodes to each other and to said rods as an integral unit with one end of said pin electrodes and anedge of said bar electrode exposed on the exterior of said envelope in position to effect recording on a recordmedium, and the opposite pin ends only exposed on the interior of said envelope for impingement by said cathode beam, said electrically non-conductive glass means including a strip of glass of uniform thickness in contact with and between the row of pin electrodes and the bar electrode, andestablishing a predetermined spacing therebetween.

2. In a cathode ray tube for use in electrostatic recording and having an electrically non-conductive envelope, means in said envelope [for generating and project: ing a cathode beam, and an electrostatic recording head rlio-rming a part of the faceplate of said envelope, the improvement of a'said head comprising a pair of electrically non-conductive elongated nods each having at least one flat side along its length, a plurality of pin electrodes,- electrically non-conductiue glass means bonding said'pin electrodes in a line spaced from each other on the flat surface of one of said rods, a bar electrode, non-conductive glass means bonding said bar clectnode to the flat.

surface of the second of said rods, electrically, non-conductive-iglass spacer means insulatingly bonding said ro ds together .as a recording head unit and establishing by contactsaid pin electrodes and said bar 'eilectrode'in closely adjacent relationship and sandwiched between said pair of holds with one end ofsaid pin electrodes and an edge I of said bar electrode exposed on the exterior of said envelope in position to effect recording on a record medium, and the opposite pin ends only exposed on the in terior of said envelope for. impingement by said cathode beam. I o 7 3. A construction according to claim 2 wherein said pair of rods ameof lead-glass, said glass means bonding said pin and bar electrodes to said pair of nodsris glass] ifrit, and said non-conductive lglaSS spacer means bonding said rods together as a unit is a thin sheet out glass of uniform thickness fuzed to a portion of said frit.

plurality O'f UIHitS, are bonded to each other to form a matrix of pin-bar electrodes -6. Anclectrostatic recording head unit comprising an} aligned row of pin electrodes, a bar electrode closely adjacent and traversing, adjacent ends of said pin electrodes, a pair of electrically non-ocnductive rod means, electri callly non-conductive lglass means insulating said pin electrodes from each other and from said bar electrode and sandwiching said electrodes between said rods and simultaneously bonding said pin and bar electrodes to each other and to said rods as an integral unit with one end of said pin electrodes and an edge of said bar electrode exposed on one side of said unit, and the opposite pin ends only exposed on the opposite side of said unit, said bar electrode extending from the sandwich parallel to and beyond one end of said rods to provide a connection, and said electrically non-conductive lglass insulating means including a planar strip of glass of uniform thick- 5 ness in contact with and between the row of pin electrodes and the bar electrode, and establishing a uniform predetermined spacing rshercoetween.

7. A construction according to claim 6 and rfiurther including a plurality of said head units bonded together to dorm a matrix of pin-bar electrodes.

References Cited in the file of this patent UNITED STATES PATENTS 10 2,918,580 Howell Dec. 22, 1959 2,952,796 Crews et al Sept. 13, 1960 FOREIGN PATENTS 1,224,349 France Feb. 8, 1960 

1. IN A CATHODE RAY ELECTROSTATIC RECORDING DEVICE HAVING A NON-CONDUCTIVE ENVELOPE, MEANS IN SAID ENVELOPE FOR GENERATING AND PROJECTING A CATHODE BEAM, AND A PINBAR ELECTROSTATIC RECORDING HEAD FORMING A PART OF THE FACEPLATE OF SAID ENVELOPE, THE IMPROVEMENT OF A SAID HEAD COMPRISING AN ALIGNED ROW OF PIN ELECTRODES CLOSELY SPACED FROM EACH OTHER, A BAR ELECTRODE CLOSELY ADJACENT AND TRAVERSING ENDS OF SAID PIN ELECTRODES, A PAIR OF ELECTRICALLY NON-CONDUCTIVE ROD MEANS, ELECTRICALLY NON-CONDUCTIVE GLASS MEANS INSULATING SAID PIN ELECTRODES FROM EACH OTHER AND FROM SAID BAR ELECTRODE AND SANDWICHING SAID ELECTRODES BETWEEN SAID RODS AND SIMULTANEOUSLY BONDING SAID PIN AND BAR ELECTRODES TO EACH OTHER AND TO SAID RODS AS AN INTEGRAL UNIT WITH ONE END OF SAID PIN ELECTRODES AND AN EDGE OF SAID BAR ELECTRODE EXPOSED ON THE EXTERIOR OF SAID ENVELOPE IN POSITION TO EFFECT RECORDING ON A RECORD MEDIUM, AND THE OPPOSITE PIN ENDS ONLY EXPOSED ON THE INTERIOR OF SAID ENVELOPE FOR IMPINGEMENT BY SAID CATHODE BEAM, SAID ELECTRICALLY NON-CONDUCTIVE GLASS MEANS INCLUDING A STRIP OF GLASS OF UNIFORM THICKNESS IN CONTACT WITH AND BETWEEN THE ROW OF PIN ELECTRODES AND THE BAR ELECTRODE AND ESTABLISHING A PREDETERMINED SPACING THEREBETWEEN. 